Analysis of Means with Unequal Sample Sizes
/****************************************************************/
/* S A S S A M P L E L I B R A R Y */
/* */
/* NAME: ANOMX2 */
/* TITLE: Analysis of Means with Unequal Sample Sizes */
/* PRODUCT: QC */
/* SYSTEM: ALL */
/* KEYS: ANOM, Analysis of Means, */
/* PROCS: SHEWHART */
/* DATA: */
/* REF: L.S. Nelson (1983), 'Exact Critical Values for */
/* Use with the Analysis of Means'. Journal of Quality */
/* Technology 15, pp. 40-44. */
/* */
/* D.O. Fulenwider (1988), 'Using SAS Software for */
/* Analysis of Means', "SAS Users Group International: */
/* Proceedings of the Thirteenth Annual Conference, */
/* 1212-1219. */
/* */
/* NOTES: This sample program uses the anomh2 macro defined */
/* in sample program ANOMH2. Those statements must be */
/* submitted before this sample program. */
/* */
/****************************************************************/
data example2;
input aggregt $ moisture ;
cards;
1 551
1 457
1 450
1 731
1 499
1 632
2 595
2 580
2 508
2 583
2 633
3 639
3 615
3 511
3 573
4 417
4 449
4 517
4 438
5 563
5 631
5 522
;
proc shewhart data=example2;
xchart moisture*aggregt /
nochart
stddevs
smethod=rmsdf
outhistory=hist2
outlimits=lim2;
run;
data hist2a;
retain sumni 0;
set hist2 end=eof;
_phase_=aggregt;
sumni+moisturen;
if eof then do;
set lim2(keep=_stddev_);
mse=(_stddev_*c4(sumni - (_n_ -1)))**2;
msedf=sumni-_n_;
call symput('mse',left(put(mse,8.3)));
call symput('msedf',left(put(msedf,8.)));
call symput('ntrt',left(put(_n_,8.)));
call symput('totn',left(put(sumni,8.)));
end;
run;
/* NOTE: alpha level is .05, halpha is calculated */
%anomh2(.05,&msedf,&ntrt);
run;
data lim2a;
retain _var_ _subgrp_ _sigmas_ _alpha_ _mean_;
length _index_ $ 4.;
if _n_ =1 then set lim2;
set hist2(keep=moisturen);
_index_=_n_;
halpha=&halpha;
hdelta=&halpha*sqrt(&mse)*sqrt((&totn-moisturen)/
(&totn*moisturen));
_lclx_=_mean_-hdelta;
_uclx_=_mean_+hdelta;
_stddev_=sqrt(&mse);
_limitn_=moisturen;
_alpha_=.05;
output;
symbol1 v=none h=3 w=20 f=;
title1 font='albany amt' h=1.5 c=black 'Analysis of Means';
title2 font='albany amt' h=.9 c=black 'Unequal Sample Sizes';
proc shewhart history=hist2a limits=lim2a;
xchart moisture*aggregt/
stddevs
tableout
readphases=('1' '2' '3' '4' '5')
readindexes=('1' '2' '3' '4' '5')
readalpha
ct=black
climits=black
ca=black
font='albany amt'
noconnect
cneedles=green
cout=orange
cframe=lio
nolegend
ucllabel='UDL'
lcllabel='LDL'
haxis=(' ' '1' '2' '3' '4' '5' ' ');
label moisturex= 'Moisture Absorption'
aggregt= 'Concrete Aggregate';
run;